For example, Patent Documents 1 to 5 disclose techniques, as a technique for controlling engine coolant flow, which may be relevant to the present invention.
Patent document 1 discloses a water pump, of an internal combustion engine, equipped with a rotary valve changing injection outlets. Patent document 2 discloses a cooling apparatus of the engine equipped with a high temperature thermostat valve and a low temperature thermostat valve. Patent document 3 discloses an automotive coolant control valve controlling the coolant distribution and the coolant flow, instead of the thermostat of a radiator and a valve of a heater. Patent document 4 discloses an automotive internal combustion engine equipped with: a first control unit feeding the coolant into a cylinder head and/or a crank case; and a main coolant pump turned on or off. Patent document 5 discloses two systems of the cooling apparatus thermostat capable of for controlling two coolant paths independently.